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The near-field photolithography system has attracted increasing attention in the micro- and nano-manufacturing field, due to the high efficiency, high resolution, and the low cost of the scheme. Nevertheless, the low quality of the nano-patterns significantly limits the industrial application of this technology. Theoretical calculations showed that the reason for the poor nano-patterns is the sharp attenuation of the surface plasmon polaritons (SPPs) in the photoresist layer. The calculation results suggest that the waveguide mode, which is composed of the chromium-equivalent dielectric layer-aluminum, can facilitate the energy flux density distribution in the photoresist layer, resulting in the enhancement of the field intensity of SPPs in the photoresist layer. This reduces the linewidth of nano-patterns, while it enhances the pattern steepness. Eventually, the focusing energy of the photoresist layer can be improved. The finite-difference time-domain method was employed to simulate and verify the theoretical results. It is found that for the rotational near-field photolithography with 355 nm laser illumination, the linewidths of the nano-patterns with and without the aluminum reflector are 17.54 nm and 65.51 nm, respectively. The robustness of the experimental results implies that the application of the aluminum reflector enhances the focusing effect in the photoresist, which can broaden the application of the near-field photolithography.

Mass loading of functional particles on the surface of nanofibers is the key to efficient heavy metal treatment. However, it is still difficult to prepare nanofibers with a large number of functional particle loads on the surface simply and efficiently, which hinders the further improvement of performance and increases the cost. Here, a new one-step strategy was developed to maximize the adhesion of graphene oxide (GO) particle to the surface of polyvinylidene fluoride (PVDF) nanofibers, which was combined with coaxial surface modification technology and blended electrospinning. The oxygen content on the as-prepared fiber surface increased from 0.44% to 9.32%, showing the maximized GO load. The increased adsorption sites and improved hydrophilicity greatly promoted the adsorption effect of Cr(VI). The adsorption capacity for Cr(VI) was 271 mg/g, and 99% removal rate could be achieved within 2 h for 20 mL Cr(VI) (100 mg/L), which was highly efficient. After five adsorption–desorption tests, the adsorption removal efficiency of the Cr(VI) maintained more than 80%, exhibiting excellent recycling performance. This simple method achieved maximum loading of functional particles on the fiber surface, realizing the efficient adsorption of heavy metal ions, which may promote the development of heavy-metal-polluted water treatment.

High-performance air filtration was the key to health protection from biological and ultrafine dust pollution. A self-supporting, three-dimensional (3D) nanofibrous membrane with curled pattern was electrospun for the filtration, of which the micro-fluffy structure displayed high-filtration efficiency and low-pressure drop. The flow field in the 3D filtration membrane was simulated to optimize the process parameters to increase the filtration performance. The qualification factor increased from 0.0274 Pa−1 to 0.0309 Pa−1 by 12.77% after the optimization of the electrospinning parameters. The best filtration efficiency and pressure drop were 93.6% and 89.0 Pa, separately. This work provides a new strategy to fabricate 3D structures through the construction of fiber morphology and promotes further improvement of air filtration performance of fibrous filters.

Highly efficient air filtration with low pressure drop is the key to air purification. In this work, a self-powered electrospun nanofiber membrane with an electrostatic adsorption effect was prepared to improve the filtration efficiency of micro/nano particles. The composite membrane was comprised of polyvinyl chloride (PVC) nanofibers and polyamide-6 (PA6) nanofibers. The triboelectric effect between the two adjacent nanofiber membranes generated electrostatic charges under the action of air vibration, by which the electrostatic adsorption with the same pressure drop was enhanced. The electrostatic voltage on the self-powered nanofiber membrane was 257.1 mV when the flow velocity was 0.1 m/s. For sodium chloride (NaCl) aerosol particles with a diameter of 0.3 μm, the removal efficiency of the self-powered composite nanofiber membrane was 98.75% and the pressure drop was 67.5 Pa, which showed a higher quality factor than the membrane without electrostatic charges. This work provides an effective way to improve the filtration performance of air filter membranes.